In general, in a vehicle such as an electric automobile or a hybrid automobile, a battery to be used as a power supply for a motor configured to drive the vehicle.
As the battery, a large-capacity battery is used in order to accelerate the vehicle by driving a motor at the time of start or during traveling of the vehicle and to control a vehicle by braking at the time of sudden stop.
In order to suppress degradation of performance caused by increase in temperature of the battery, it is necessary to forcibly cool the battery through use of a cooler.
As the above-mentioned type of a cooler of the related art, there has been known a cooler having the following structure. That is, a refrigerant passage is formed in a cooling plate (cooler) arranged in a bottom portion of a battery. The cooler is cooled with vaporization heat of a refrigerant supplied to the refrigerant passage, and heat of the battery is transmitted to the cooled cooler, to thereby cool the battery (see, for example, Patent Literature 1).
As one mode of the cooler in Patent Literature 1, an aluminum flat pipe including a plurality of refrigerant passages parallel to each other is used.
When the aluminum flat pipe is used as the cooler, as illustrated in FIG. 13, a height dimension can be reduced through use of a cooling plate a having a flat shape and including a plurality of refrigerant passages c partitioned by a plurality of partition walls b parallel to each other along a longitudinal direction.
Further, in order to distribute the refrigerant in the cooler, it is necessary to connect a refrigerant inlet pipe and a refrigerant outlet pipe to the refrigerant passages c formed in the cooling plate a.
In this case, the following structure is conceivable. As illustrated in FIG. 13 and FIG. 14, a first joining member f1 including a refrigerant inlet connection pipe d and a refrigerant outlet connection pipe e is brought into abutment against and joined to one end of the cooling plate a, and a second joining member f2 having a flow passage (not shown) causing refrigerant passages c on an inlet side and refrigerant passages c on an outlet side to communicate to each other is brought into abutment against and joined to another end of the cooling plate a.
Further, even when the above-mentioned cooling plate is not used in the cooler, it is at least necessary to join the joining member including the refrigerant inlet connection pipe and the refrigerant outlet connection pipe to the cooler.